nanog mailing list archives

Re: QUIC traffic throttled on AT&T residential


From: Blake Hudson <blake () ispn net>
Date: Wed, 19 Feb 2020 13:54:27 -0600


On 2/18/2020 6:00 PM, Ca By wrote:
On Tue, Feb 18, 2020 at 5:44 PM Daniel Sterling <sterling.daniel () gmail com <mailto:sterling.daniel () gmail com>> wrote:

    I've AT&T fiber (in RTP, NC) (AS7018) and I notice UDP QUIC traffic
    from google (esp. youtube) becomes very slow after a time.

    This especially occurs with ipv4 connections. I'm not the only one to
    notice; a web search for e.g. "Extremely Poor Youtube TV Performance"
    notes the issue.

    I assume traffic is being throttled on AT&T's side. And it's not done
    with their CPE; I'm bypassing their NAT box and connecting my laptop
    directly to the ONT.

    A quick google search shows people are aware that QUIC can look like
    DoS traffic -- but how widely known is this problem? It may become
    worse if / when sites transition to HTTP/3

    For now I reject UDP 443 on the client firewall. Applications using
    QUIC client libraries then fallback to TCP. This works well and I have
    no issues with latency or throughput when using TCP.

    May I naively ask if Google staff are working with AT&T to address
    this?


Sounds like you found the answer, ATT just needs to scale up your rejection approach that is proven to work well.

Yes, most ddos traffic is ipv4 udp and yes Google was made aware that they would be mixing with bad company in the pool of ipv4 udp traffic ... but they have reasons.

I am not a fan of quic or any udp traffic. My suggestion was that Google use an new L4 instead of UDP, but that was too hard for the Googlers.

So here we are.

Just say no to udp.

Isn't this exactly why Net Neutrality is a thing: So that people (or companies) are free to develop new applications or enhance existing ones without running into a quagmire of different policies implemented by any number of different networks between the application developer and the application's users?

For what it's worth, Cox cable also treats UDP traffic differently - impacting the performance of VPNs using UDP. Cox provides a list of blocked ports on their website, but makes no mention that they throttle or otherwise treat UDP as a special case. I'm guessing ATT doesn't disclose this policy transparently either.


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